Question

If the magnetic field of a light wave oscillates parallel to y-axis and is given by $B_y=B_m\sin (kz-\omega t)$, the direction of wave travel and the axis along which the electric vector oscillates is :

• A. + ve y - axis, z - axis
• B. -ve z - axis, x - axis
• C. -ve x - axis , y - axis
• D. - ve x - axis, z - axis

Answer 1

The correct option is B -ve z - axis, x - axis

Given $B_y=B_m\sin (kz-\omega t)$. According to this equation the direction of propagation is along z axis. The direction of electric vector must be perpendicular both y and z-axis, So it is along x-axis.